The transmission control protocol (TCP) is the most common protocol on the Internet. It relies on acknowledgment signals (ACKs) to estimate how quickly a sender can transmit without loss and treats packet latency as an indicator for loss. The wireless protocol 802.11ac is the most common wireless access protocol. The TCP protocol does not generally work well with the newer and faster wireless protocols such as 802.11ac. For wireless to achieve such high speeds, such as 1.3 Gbit/s, the 802.11 protocol relies on aggregation of packets in a frame. TCP however does not understand and is not configured to necessarily work well with the aggregation component of 802.11. The acknowledgement structure in TCP and the latency that is introduced because devices must contend for the wireless channel to send a TCP ACK can ultimately lead to devices aggregating less packets for a frame to transmit on the wireless channel, which reduces the efficiency of the system.
Access to the wireless medium (the radio link) according to the 802.11 protocol is controlled by coordination functions. One such function is the distributed coordination function (DCF) which requires stations to first check to see if the radio link is clear before transmitting data. To avoid collisions, stations use a random backoff after each frame is transmitted with the first transmitter seizing the channel. The DCF allows multiple independent stations to interact without central control. Before attempting to transmit, each station checks whether the wireless medium is idle. If the wireless medium is not idle, stations defer to each other and employ an orderly exponential backup algorithm to avoid collisions.
There are basic rules that apply to transmissions using the DCF. Those of skill in the art will understand the details of these rules. For purposes of this disclosure, it is simply noted that medium access is expensive in this environment, so once a device gains access to the radio link, it will desire to send as much data as possible. Accordingly, the device or system will intentionally induce packet latency in order to aggregate packets into a single frame. In another aspect, a sending device may aggregate less packets than it could because it has access to the wireless channel and wants to send something. The goals of introducing latency as well as aggregating packets into a single frame are fundamentally at odds with one another. Furthermore, the medium access process introduces additional, irregular latency into the use of ACKs, which only exacerbates the issue.